SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5294aca52578a5123cb33ac70c65edb90bf3a01e086471fd94b758788995bf5b' 
  AND token = 'lCNFolid6XKD3aEsiVlDNXP44RRJA7VJX7tSw40GmjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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