SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00fbdc553eb04fb37cde0fd7f107a309fc5815db0461961c8d3c69645adca0f5' 
  AND token = 'u1/G01uT1NDYjyGLTV+qte0Pwg47pU9Q2K3Mrp3yKIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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