SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dad7133f2184ca9e7c64cc40338274eedbaf36b329f0e6e62be19f5e2950ac12' 
  AND token = 'lxJ23jjmj2EhKqHAKgmCFFc1Hy71h5XemwHiHQCrS/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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