SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e4e67b0059e4a0575a1e2bea2c51c950f42ddebf2fe70ae89f6d4c6461a5bc3' 
  AND token = 'Qqwq6Wr3Pr7jhEdLlHDwwwFP9SNOy9p25FXWPQfJl/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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