SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3186c77daa1178db7e96470f2a5006d4f8a444f9566ddfc505781eaf65277ca' 
  AND token = 'KzdAT/ZJzfduUu62ZOlrQRTZFYuFbjbmFOlkBFbyqeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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