SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c6a0974aeb101db9f84f2c5fc5963381c0baf0f2451051774cd303a093eca1' 
  AND token = 'kgVct76NvRvhVPT2/65csV1+NoJSpyk5oKMTzZc1c2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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