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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4236e3fd0ea1f8a8dc88d70e3e0515265c53f2358d801fe74af259ee7ee3278a' 
  AND token = 'Cb+8NTj3k9s3y3SWd4ZR0cD/fAQtwKrULPoDUaSMfPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}