SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be936c4ba4ee39671fdb686bbedb0bd4f5d56effcca0d0fb7eb3f317383c180a' 
  AND token = 'i9dCdQUhvcOFedUcOgv/ObAba/zzLPGAObRu+ZRBcmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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