SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b66c3cd8cb01d9fc2e6b733db2d4df803efed7c53394fb4d641e219b4ad8be36' 
  AND token = 'zF8La/oVgCSYC6zLkECTfpyTPGH0KAnCBsJUcSjJGW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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