SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f22d8f7db0c5b6a525d20eb05c361d36448988bdf610f74745f2c47da3c874' 
  AND token = 'BPzukzTIOUFXZVuV5a1wfOvKu3z3ZqyDjQpCTp3ITOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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