SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2508709b7f7e06dc3417563aed0413b6a8af2072d5a7bc312159301494b2ce34' 
  AND token = 'NmpupuwoOSHDhugEFSm10Ht/u4i68l8klFPOvDfTwBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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