SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4656f6839f0b24baf65eaf4b3035319b46cf9bcd68a212ad36822d8987a7f6c' 
  AND token = 'Apy3z1+41HVTX32+KcvK7GTczWiUkLVSzYPyRShWQJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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