SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78bdc664a5ea5bd84d86a0448d3e84fca9c8b3d312bfd1724382624c55916c40' 
  AND token = '2djavur8qp5RTfo1W5MuSRDoOVSZ8JC2qMdJJAZqZfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00127

JSON explain

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