SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0317b60d47c390a31d8718581bf2624d43b21b9c62409a0c3211c04996960e9' 
  AND token = 'QOhXGuEDdn9yfkgRE8GbJx2YR2vbDIBB4/Vwlrt8yFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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