SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd272a9a7973b16255ac1aadae936dd4ead97265f6c835f8b9cf106b12116dd67' 
  AND token = '0wJwkvFCiCrf1vaq1nET1ZSc2FUL7+3N3cUXMKlQjsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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