SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0141daf526fa5337758df8b42fe392aa899244263877c47799ea4204016f174' 
  AND token = 'Ci6PvwIil5Rd+KD4je23Gl57IfWKFvSEhr+9njF/SVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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