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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cea2fd62fff4762f9b0aba8d4eac987c2cd7bc0025fc7d47393a3c05064add1' 
  AND token = '0NRKI5zr4B+3xXzwoBUqNPrGPSi9Hz06/2Lci2jLd8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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