SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b98fc74f76cfab6d53bab791618571e7571c38f74f3a9de20375e2e6a9fd5029' 
  AND token = 'AnvzL4Jz1s0ulJn2BEZSgrOmzd1Pc4e+N+wH68YQKlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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