SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a0b01dfbcd80a31915cf04fca5b8e463ce634745b68192ee778f14173d4a0e1' 
  AND token = 'XjK9gb7d8znzgYq6eakJKUvCrZptqsXmGMHXxL8mfdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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