SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0785248554022ee1038906398ea554eed585bfd785424a71d30e058c9f0da8e' 
  AND token = 'nhxcccW9VvCNuSwoasqn7hW9VCycCWd20jUNJB2yYs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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