SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a7471eb772f5f653e4c8c1b54b99e20c4bb6af09379635c15b8f2921528733' 
  AND token = 'hCuPCCUvMpJoR/rCrJ8wUjaw9lzMustQWPdPn5498lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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