SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fc0890566776d524c09b5201cf4ecfc025dfeb8f114e58ded441c9d8ed5eac1' 
  AND token = '3f7GPxZKiprq4jGCTSAxx7zhYL9qH5Rx+VNUoPKw/bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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