SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b31a4cd527e1e9e3554d6f29c6047c5dc04ac7f403704a817817833327f0e084' 
  AND token = 'gZLYrBwKr+bbe2lQpspxGACswq3JKUtnOKXV6b6ltW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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