SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f7cb8bfafa0469fb721c2db5f1e7779a8b6dcd3368b3bc252e09d569c07d1552' 
  AND token = 'UPCGE7vvNz0ua3zO3WB7Q2RoxgwAiMOmH9Et5nTdNY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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