SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18853f676870fbc1128f30da409d69ecc76e2023ef9f07361ff72348d186f264' 
  AND token = 'nP4v1uPdUE+0C6JfAkkEXyiRkswN5f+9Zobur0ZMa6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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