SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02fed257a123ce3968940a6d1782abfe216402fb3979fbbb4423e0a1d0dee328' 
  AND token = 'izBjkiNVwRcCmiCNAylz/p17pufM8nVD1XPDQmeBCzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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