SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84572ed731df23aab24155872fae14b819263bbdc5d8922e544ac51da5683ce5' 
  AND token = 'mR/H/wYRE7hqgJxuZwAoAj2qZmR3qlR1WwsoMeK4zjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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