SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5d2dd041c8297bf040cbb23970ca786ef0bd01a2936200b2dd983fb1c46e727' 
  AND token = 'LeFL0+lQfTITasVPUUNUSAePNCiFTdeGAt/RMrjcTN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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