SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbe80ed291aa73ed325333405269b718dda47f82f55011a9b959b54ab8324846' 
  AND token = 'SVZFPIy7xAi7yoG3SoO5JtqsRCW6SNP96b3eAHFIz3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}