SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78247c0f01d968cc9806a51964b177c4aeaa35665abe058de17a1c69d2313eac' 
  AND token = 't0hz85TRPOumAUgduZsZhpan0c94ReYTIVUWANjhgaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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